AND OBSERVATIONS ON LAC. 47 



The firfl: chemift of eminence who mentions it, and the only Experiments of 

 one who has fubjecf ed it to any thing like a regular examination, eo c °** ie 

 is the younger Geoffroy, whofe Paper is publifhed in the Mem. 

 del' Acad., de Paris for the year 1714.* In this Paper, Mr. 

 Geoffroy feems to have been chiefly induced to examine it on 

 account of its tinging fubflance; but he neverthelefs has not 

 neglecled the fubfiance which conftitutes the cells. This he 

 confiders to be a fort of wax, very diftincf from the nature of 

 gum or refin. But it is to be obferved, that he formed this 

 opinion, not fo much upon the refults of chemical experiments, 

 as upon the cellular conflruclion obferved in the flick lac, 

 which, as he juftly remarks, demonftrates it to be formed by 

 infe£ts, after the manner that the honeycomb is formed by bees; 

 and that it is not therefore, as fome have fuppofed, a gum or 

 refin, which has exuded from vegetables {imply punctured by 

 infecls.f 



Geoffroy and Lemery obtained from lac, by diftillation,_andLemery. 

 fome acid liquor, and a butyraceous fubflance. Moreover, 

 Geoffroy obferves, that when flick lac was thus treated, fome 

 ammonia was aifo obtained, but not when feed lac was em- 

 ployed. 



He alfo mentions another fort of lac, brought from Mada- Another lac 

 gafcar, and called by the natives Lit-in-bitfic. This fubflance, wl V ch a ^ ars 

 he fays, is fcarcely to be diflinguifhed from bees-wax, which it p e -laof China, 

 much referable* in colour and odour; and that it is produced by 

 a grayiih infecl, much larger than the chermes lacca. It is evi- 

 dent however, from GeofFroy's defcription, that this fubflance 

 is very different from the common lac; and there can be little 

 doubt, but that it is the fame as that which was, a few year* 

 ago, examined by Dr. Pearfon, under the name of white lac, 

 a fubflance refembling the Pe-la of the Chinefe. % 



Geoffroy (as I have flated) confidered lac as a fort of wax . Notions of che- 

 and fince his time it has fcarcely, if at all, been fubjeaeri to mifts concerning 



* Obfervations fur la Gomme Lacque, et fur les autres Matieres 

 animales qui fourniflent la Teinture de Pourpre. Par. M. Geoffroy 

 le jeune. Mem. del" Acad. 1714. p 121. 



f Mr. Kerr obferves, that as a red. fubflance is obtained by inci- 

 fion from the plafo tree, very analogous to lac, it is probable, that 

 the infects have little trouble in animal izing the fap of thefe trees, in 

 the formation of their cells. Phil. Trans. 1781, p. 377. 



X Phil. Trans. 1794, p. 383. 



chemical 



